Disclaimer: I am not sure this subject hasn't been touched before and I'm not even sure it isn't nonsense.

In real life ladders prefer a vertical position. Not so in go where they tend to have a diagonal direction.
In go we know the ladder as a sequence of moves in which alternating an attacker threatens to capture and a defender threatens to escape. Typically this repeats in a fixed pattern until an edge is reached or a so called ladderbreaker. This is the global aspect of ladders. Its success might be decided far, far away. If possible a local solution is preferable.
Usually we only consider diagonal ladders; they resemble a staircase. The ladder than develops parallel to a diagonal of the board.
I propose also to consider vertical ladders of which the next diagram is the simplest ( boring ) example.
first edit: please skip the hidden part it is rightly dismantled by Li Kao.

Click Here To Show Diagram Code

[go]$$c dia 1: B to kill
$$ . . . . . . |
$$ . . . . . O |
$$ . . . . X O |
$$ . . . . X O |
$$ . . , . X O |
$$ . X X X O O |
$$ . X O O X X |
$$ . . . . X . |
$$ ------------+[/go]

To kill B has to climb the ladder, chasing W up until W breaks his neck against the ceiling.

Like the diagonal ladder also the vertical ladder has more exiting variants.
Here an example resulting from a trick play in the tsuke-hiki joseki after a tenuki.

Click Here To Show Diagram Code

[go]$$c dia 2a 6 tenuki
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . 8 4 3 5 . . . |
$$ , . 0 9 7 2 , 1 . . |
$$ . . . . . . . . . . |[/go]

Click Here To Show Diagram Code

[go]$$c dia 2b trickplay 5 at a
$$ --------------------------+
$$ . . . . . . 0 . . . . . . |
$$ . . . . 9 2 a 6 . . . . . |
$$ . . 8 c 3 1 O O X X . . . |
$$ . . . , 4 O X X O , X . . |
$$ . . . . . . . b 7 . . . . |
$$ . . . . . . . . . . . . . |[/go]

after 4 B fears both the ( diagonal ) ladder at b and the capture at c ( miai ) so he tries the trickplay 5 at a.
7 defeats the diagonal ladder; 8 defeats the trickplay by a vertical ladder as shown in the next diagrams.

Click Here To Show Diagram Code

[go]$$c dia 2c
$$ ----------------------------+
$$ . . . 6 3 5 . O . . . . . . |
$$ . . 1 X 2 X O . O . . . . . |
$$ . . . O 4 X X O O X X . . . |
$$ . . . . O O O X X O , X . . |
$$ . . . . . . . . . X . . . . |
$$ . . . . . . . . . . . . . . |[/go]

The ladder gets its base.

Click Here To Show Diagram Code

[go]$$c dia 2d B gets killed in the opposite corner
$$ +---------------------------------------+
$$ | . . . . . 8 5 1 . X X . O . . . . . . |
$$ | . . . . 7 3 4 X X O X O . O . . . . . |
$$ | . . . . . 6 2 . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Click Here To Show Diagram Code

[go]$$c dia 2e 8 at a
$$ +---------------------------------------+
$$ | . 9 a 5 1 . X X . X X . O . . . . . . |
$$ | . 7 3 4 X X O X X O X O . O . . . . . |
$$ | . 0 6 2 . O O . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Question1: Is this last vertical ladder the only way to kill B's top or is there a local solution?
Question2: Anyone another type of a vertical ladder other than the two types shown here?

first edit: hidden the example critized in the next post by Li Kao ( thx )

_________________
I think I am so I think I am.

I don't understand how to kill as black.

Click Here To Show Diagram Code

[go]$$c B to move first
$$ . . . . . . 2 . |
$$ . . . . . . 1 O |
$$ . . . . X . X O |
$$ . . . . O X X O |
$$ . . . . O X X O |
$$ . O O O O X O O |
$$ . O X X X O X . |
$$ . . . X . O . X |
$$ ----------------+[/go]

_________________
Sanity is for the weak.

you are too smart . I'll repair this example ( shouldn't be too difficult ). What about my other example. Isn't it cute?

_________________
I think I am so I think I am.

The other example looks to me like it contains mistakes too, but I'll leave it to a stronger player to figure it out.

_________________
Sanity is for the weak.

This is how I've always seen it played:

Click Here To Show Diagram Code

[go]$$c
$$ ----------------------------+
$$ . . 7 6 3 5 8 O . . . . . . |
$$ . . 1 X 2 X O . O . . . . . |
$$ . 0 . O 4 X X O O X X . . . |
$$ . . . . O O O X X O , X . . |
$$ . . . . . . . . . X . . . . |
$$ . . . . . . . . . . . . . . |[/go]

Click Here To Show Diagram Code

[go]$$c B gets killed in the opposite corner
$$ +---------------------------------------+
$$ | . . . . . 5 3 X X X X O O . . . . . . |
$$ | . . . . . 1 2 X X O X O . O . . . . . |
$$ | . . . . 6 . O 4 O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Basically the same thing.

When I play out sequences in my head (i.e., not for an actual game being physically played), half the time they devolve into the sequence above. Yet I've never actually had an opportunity to use that move in a game.

I agree, the position is pretty cool.

_________________
We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

I thought for a moment your solution is local. But it isn't. B plays d18 next and the pattern repeats. It is another vertical ladder - maybe the same in another disguise - that accomplishes the same thing.

_________________
I think I am so I think I am.

BTW, I think that the proper word here is orthogonal, not vertical.

_________________
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